This invention relates to a method for casting or molding an article of jewelry, and more particularly, to a method for producing a bored out or hollow jewelry article such as a ring.
There are many well known processes used in the large volume production of jewelry. Such processes include die striking, casting and electroforming, all of which are used for producing metallic jewelry articles. Such production methods are capable of facilitating high volume, high speed production with very good reproducibility. For example, using permanent-mold casting or injection molding techniques, a single mold cavity may be used repeatedly to produce, at a low cost, a virtually unlimited number of jewelry articles of intricate detail and varying size.
In order to reduce production costs in the manufacture of jewelry articles, previous improvements have generally focused upon better equipment; very little effort has been directed to actually modifying the jewelry article that is produced in order to reduce the cost thereof. One way, of course, of reducing production costs is to reduce the amount of precious or semi-precious metal that is used in producing a jewelry article, while still achieving the visual presentation that is desired by the jewelry designer.
One such prior method involves the use of an acid or water-soluble wax insert disposed in a mold cavity in order to form a mold of a partially or completely hollow article. According to this technique, a soluble wax core insert is placed in a mold cavity. Then a molten wax is injected into the mold cavity, filling the cavity and surrounding the core insert. The core insert is then removed in order to produce a wax article having a hollow core.
In the prior art, the use of soluble wax core inserts has been less than desirable. In the first place, there have been difficulties in achieving proper alignment of the insert and in preventing random movement or shifting of the insert during waxing or casting. In addition, the prior art has failed to teach the use of a soluble wax core insert such that a hollow or bored out space is defined within the ring which extends virtually along the entire arcuate length thereof.
Moreover, in the prior art U.S. Pat. No. 5,718,278 to Baum, it is stated that it is not possible to produce a ring having an inner round radius design utilizing a vertically oriented mold configuration. However, the Baum process which utilizes a horizontally oriented mold configuration is less than desirable since it is not able to produce a ring which is hollowed or bored out to an arcuate content of 200xc2x0 and up to or approaching 360xc2x0.
Generally speaking, in accordance with the invention, there is provided a method or process for fabricating a hollow jewelry article which is hollowed or bored out to an arcuate extent of 200xc2x0 or greater. In accordance with this process, a metal ring model is prepared comprising a solid shank and a metal plate supported along the internal perimeter of the shank and arcuately extending at least 200xc2x0 therealong. A first metal mold is produced from the metal ring model having the external shape of the jewelry article to be manufactured. From this mold, a wax model of the jewelry article is produced which is first filed down and then cast in order to form a metal model of a core insert; the core insert, like the ring model, has a plate disposed along the perimeter of the shank. This core insert is used to produce a second metal mold. This second mold may then be used repeatedly in order to form a soluble wax core insert model which is then inserted into the cavity of the first mold in order to define the hollow region of the article. A non-soluble wax is then introduced into the first mold for completely surrounding the soluble wax core insert. The non-soluble wax then hardens and the entire unit is removed from the first mold, including the soluble wax core. The core is then removed by, a suitable water soluble or chemical mechanism. The remaining wax model contains a hollow core running along a substantial portion of the arcuate length thereof. The wax model is then cast in order to form the inventive ring design.
Because the ring model includes a plate supported along the internal perimeter of the shank, it is possible to produce a core insert which arcuately extends at 200xc2x0 or greater, thereby enabling the production of a ring or other jewelry article which is bored out or hollowed within the shank thereof to an extent for greater than what is taught by the prior art.
It is therefore an object of the invention to produce a ring design having a shank which is hollowed to an arcuate extent of at least 200xc2x0.
Another object is to produce a ring design which uses less metal but still exhibits the same physical appearance.
Yet a further object of the invention is to produce a ring design in which the inside surface of the shank is substantially flat with rounded edges.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others thereof, as well as an article of manufacture produced by carrying out these steps, and which possesses the features, properties and relation of elements, all of which will be exemplified in the process and article hereinafter disclosed and described, and the scope of the invention will be indicated in the claims.